diff --git a/apps/extension/entrypoints/sidepanel/agents-session-list.test.tsx b/apps/extension/entrypoints/sidepanel/agents-session-list.test.tsx
new file mode 100644
index 0000000000..d49bd2c0a1
--- /dev/null
+++ b/apps/extension/entrypoints/sidepanel/agents-session-list.test.tsx
@@ -0,0 +1,170 @@
+/* eslint-disable jest/max-expects, promise/avoid-new -- one flow needs many focus assertions; the debounce flush needs a real-timer sleep */
+// @vitest-environment jsdom
+
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
+import { fireEvent, render, screen, waitFor } from '@testing-library/react';
+import { StrictMode } from 'react';
+import { describe, expect, it, vi } from 'vitest';
+import { AgentsMode } from './agents-mode';
+import type { ExtensionAgentsContextValue } from './agents-provider';
+
+/**
+ * The provider value must be reachable from the hoisted vi.mock factory, so it
+ * lives in vi.hoisted storage and is assigned per test.
+ */
+const mocks = vi.hoisted(() => ({
+  value: null as ExtensionAgentsContextValue | null,
+}));
+
+// eslint-disable-next-line vitest/prefer-import-in-mock, jest/no-untyped-mock-factory -- provider value is assigned per test from vi.hoisted storage
+vi.mock('./agents-provider', () => ({
+  useExtensionAgents: (): ExtensionAgentsContextValue => {
+    if (mocks.value === null) {
+      throw new Error('useExtensionAgents test value was not assigned');
+    }
+    return mocks.value;
+  },
+}));
+
+const ACTIVE_SESSIONS = [
+  {
+    connectionId: 'cli-owner-1',
+    gitBranch: 'fix/login',
+    gitUrl: 'https://github.com/org/repo',
+    id: 'ses_active0000000000000000001',
+    status: 'running',
+    title: 'Fix login bug',
+  },
+];
+
+const HISTORY_SESSIONS = [
+  {
+    session_id: 'ses_hist00000000000000000001',
+    title: 'Refactor auth module',
+    updated_at: '2026-08-30T12:00:00.000Z',
+  },
+  {
+    session_id: 'ses_hist00000000000000000002',
+    title: 'Fix login flake',
+    updated_at: '2026-08-29T12:00:00.000Z',
+  },
+  {
+    session_id: 'ses_hist00000000000000000003',
+    title: 'Configure CI',
+    updated_at: '2026-08-28T12:00:00.000Z',
+  },
+];
+
+const createTrpcStub = () => ({
+  activeSessions: {
+    list: {
+      // React Query awaits the plain result, so a non-promise return is enough here.
+      query: vi.fn(() => ({ sessions: ACTIVE_SESSIONS })),
+    },
+  },
+  cliSessionsV2: {
+    list: {
+      query: vi.fn(() => ({ cliSessions: HISTORY_SESSIONS, nextCursor: null })),
+    },
+    search: {
+      query: vi.fn((input: { search_string: string }) => {
+        const term = input.search_string.toLowerCase();
+        return {
+          results: HISTORY_SESSIONS.filter(session => session.title.toLowerCase().includes(term)),
+        };
+      }),
+    },
+  },
+});
+
+const unsubscribe = (): void => {};
+
+const createAgentsValue = (trpcClient: unknown): ExtensionAgentsContextValue => {
+  const context = {
+    manager: {},
+    organizationId: null,
+    store: {},
+    trpcClient,
+    userWebConnection: {
+      isConnected: () => true,
+      onConnectionChange: vi.fn(() => unsubscribe),
+      onSessionEvent: vi.fn(() => unsubscribe),
+    },
+  };
+  // eslint-disable-next-line @typescript-eslint/no-unsafe-type-assertion -- test double for the provider context; only trpcClient and userWebConnection are exercised
+  return context as unknown as ExtensionAgentsContextValue;
+};
+
+const renderSessionList = (): void => {
+  const queryClient = new QueryClient({
+    defaultOptions: {
+      queries: { refetchOnWindowFocus: false, retry: false },
+    },
+  });
+  // Render through AgentsMode, the live parent of the session list; the provider it reads from is mocked above.
+  render(
+    <StrictMode>
+      <QueryClientProvider client={queryClient}>
+        <AgentsMode />
+      </QueryClientProvider>
+    </StrictMode>
+  );
+};
+
+/** Flush the 300 ms search debounce and any state updates it schedules. */
+const flushDebounce = async (): Promise<void> => {
+  await new Promise(resolve => {
+    setTimeout(resolve, 350);
+  });
+};
+
+/**
+ * Reproduces the reported defect: focus the session-list search field, type
+ * three characters, and confirm focus survives every keystroke whose results
+ * update. The search below the 2-character minimum updates no results, so the
+ * result updates happen on keystrokes 2 ('fi') and 3 ('fix').
+ */
+describe('agents session list search focus', () => {
+  it('keeps focus on the search input while typed results update', async () => {
+    const trpcClient = createTrpcStub();
+    mocks.value = createAgentsValue(trpcClient);
+    renderSessionList();
+
+    // History rows render first; the search box is visible with results present.
+    await screen.findByText('Refactor auth module');
+    // eslint-disable-next-line @typescript-eslint/no-unsafe-type-assertion -- the label is the search input by construction
+    const input = screen.getByLabelText('Search sessions') as HTMLInputElement;
+    input.focus();
+    expect(document.activeElement).toBe(input);
+
+    // Keystroke 1: 'f' — below the search minimum, results do not change.
+    fireEvent.change(input, { target: { value: 'f' } });
+    await flushDebounce();
+    expect(trpcClient.cliSessionsV2.search.query).not.toHaveBeenCalled();
+    expect(document.activeElement).toBe(input);
+
+    // Keystroke 2: 'fi' — results update from history rows to search rows.
+    fireEvent.change(input, { target: { value: 'fi' } });
+    await waitFor(() => {
+      expect(trpcClient.cliSessionsV2.search.query).toHaveBeenCalledWith(
+        expect.objectContaining({ search_string: 'fi' })
+      );
+    });
+    await screen.findByText('Fix login flake');
+    expect(screen.queryByText('Refactor auth module')).toBeNull();
+    expect(document.activeElement).toBe(input);
+
+    // Keystroke 3: 'fix' — result set narrows to a single row.
+    fireEvent.change(input, { target: { value: 'fix' } });
+    await waitFor(() => {
+      expect(trpcClient.cliSessionsV2.search.query).toHaveBeenCalledWith(
+        expect.objectContaining({ search_string: 'fix' })
+      );
+    });
+    await waitFor(() => {
+      expect(screen.queryByText('Configure CI')).toBeNull();
+    });
+    expect(screen.getByText('Fix login flake')).toBeTruthy();
+    expect(document.activeElement).toBe(input);
+  });
+});